Marine microorganisms sustain the oceanic life support system and its underlying biogeochemical cycles. On the molecular level, microbes underpin these processes with the help of proteins, especially metal-containing enzymes: biochemical machines that help microbes acquire, trade, transform, and recycle essential nutrients. Elucidating the molecular mechanisms of these microbial metalloenzymes is instrumental for predicting phytoplankton responses to changing environmental conditions.

The entirety of proteins present in pure cultures of single microbes (proteome) or natural mixed microbial communities (metaproteome) directly reflects the functional status of the organisms. For example, highly responsive protein biomarkers indicate nutrient stress levels. As such, proteomics is a powerful tool to understand cellular physiology, metabolic pathways, and adaptive responses to environmental conditions of marine plankton, thus enabling new insights into function, interactions, and ecosystem-level processes.

The biogeochemical cycles of macronutrients (e.g. C, N P) and trace metals (e.g. Fe, Zn, Mn) can no longer be studied in isolation: they are tightly interwoven, often through microbial metalloprotein-based processes that link availability, speciation, and recycling of multiple elements simultaneously. Understanding the spatial and temporal dynamics of these interconnections, especially in the context of anthropogenic nutrient inputs, is crucial for predicting and constraining large-scale biogeochemical patterns.